I have an Oppo BD105 and recently I purchased an SUT for my phono setup.  Now the gain has swung the other way.  In other words, the phono setup is louder at the input than the CD player and much more satisfying as it seems that it better matched to the input sensivity of the Rachael.  Would a Zstage help in this regard with the CD player, similar to the SUT for the phono system?

A few quick thoughts:

1.) Your phono setup may ultimately just be of a higher quality than your digital setup and if that's the case, you won't be able to get to that level of resolution just by raising the gain of your digital source.

2.) The Oppo does have a digital volume control.  Make sure it is set to it's max range.

3.) I have a Zstage and it's sort of a double edged sword.  Yes, you can raise the gain on your source and even get a little more body to your sound, but it does come at slight loss of transparency.  So you are trading one set of advantages for another.

The more I think about it, in the actual experience, I am becoming less sure of what transparency is....that is, when using a very revealing source....AND TUBE gear that is built with a lot of potential for transparency! Depending on how I tube, cable and foot the Zstage or CSP3 I can make the whole less revealing, more revealing, warmer, cooler...whatever. But also, I can ride the gains with both and increase or decrease the intensity of the particular vibe they offer in the overall sound. With either the Zstage or CSP3, this is a great tool in my book, making it easier to get the most out of varied recording balances.

One factor I look at is that the pre is more about altering the source than the amp. Another is the obvious thing that more wire, resistors, caps, tubes etc in a signal path reduces transparency. The wildcard with transparent pieces is that you can really make them sound quite different with the tubes you choose, the power cable, ICs, feet, the power you feed them, etc.

I am very likely more captured by detail and "revealing" than many, and I have been able to make my Torii sound more "transparent" and dynamic with the right tube in the Zstage. I can also make it warmer and more veiled, but with my favorite 50s Siemens 12AT7 and a few others, how the Zstage shifts the sound of the source can be gorgeously revealing. I do have a jupiter cap in mine though, and it was definitely more veiled before that upgrade. The cool thing is that you can set the Zstage and CSP3 up to be a little more on the revealing side than the amp, giving the whole more flexibility depending on how much volume you give them in the balance.

Even with the more complicated CSP3, I have been able to more-or-less match the revealing qualities of the Torii with the right cables, feet and tubes, in part, by introducing a certain level of revealing "transparency" from its OTL circuit. I have some great cables and tubes though!

That said, the ZBIT sounds like a really cool tool that must be a beautiful thing, though like the Zstage, it is a simple circuit, but it is another circuit with cables! The question becomes, does the extra circuit potentiate qualities that make things better?

I agree seikosha. I just find that detail, especially micro detail, is a good reference for transparency. It seems quite fragile, and if it is not there, a lot of what makes musical authenticity is lost, also indicating something is not bringing it out in the first place, or something is masking it.

I think terminology is difficult with music and musical presentation, it is so complex. "Transparency" seems about no real modifications to the music by gear and room, no colors or veils. And solid state folks might say tube gear is colored with micro distortions, harmonics, organic warmth etc, when to me, these things done well can make music sound more like real music.

Maybe this is why I prefer "revealing" in general, seeming a good descriptor for what gear can do in relation to musical presentation, rather than what it doesn't do. If very "revealing," a lot of the countless aspects of the complexity of real music are possible... And since we generally have no reference to the recording room, gear, and engineer preferences, my reference is: "does it sound like real instruments in a good room" ...does it reveal the things you describe in a natural way.

Taken a step further, as things get more refined, I find music here generally sounds better than I have heard in studios, or even in most live venues. The implication is that gear, room, and tuning can make many recordings better...refining the presentation of the base recording. Well done tubes seem to be able to do just this, potentially enhancing recordings to sound more like music: natural harmonics and textures; spacial information from empty space to soundstage saturation and ambience; inner detail and micro detail, filling in and around denser tonal information with complexity.....very like real music. I hear it everywhere these days, helping to define edges complex enough to be without edginess; "realness" cues from drum hits, to vibration and reverberation of skin and wood, to the ambient decays helping to define space; rosin on strings; wetness of reeds; air in a voice; textures and articulations that help define natural timbre no matter the instrument; harmonic and ambient information close and far....if we are lucky, it all helps our room feel like the room the music is in.

In reference to adding gear I agree that revealing and transparency are important. And adding a stage has to reduce transparency to some degree by adding stuff for the signal path. But then, assuming the gear has potential for transparency to begin with, I find it can depend as much on the gear's cables, tubes, feet, and power source/filtering...that these things can be used to compensate for transparency losses, while enhancing the potential of the piece of gear.

Everything in my system and room is selected, modded, and tuned to a revealing end (without sacrificing musicality), and additions can all be heard. So it took took a lot of trial and error to add pre stages without veils, while enhancing the music with those sort of luminous tube qualities they can provide... spaciousness, clarity, harmonics and dynamics, and organic presentation. And oddly, in the context of "revealing," the more complex CSP3, once fine tuned, does it all better to me. The end result is a system/room that is very revealing, musical and more flexible for variable recording qualities. I thought I would have to give up the CSP3 after adjusting to the MKIV alone, but finally I got there and love what the CSP3 offers.

Though this covers more than volume tuning as riknbkr330 asked about, these are some of my personal perceptions and experience with the musical potential of Decware pre tools.